This article's content is marked as Mature

The page William Birkin contains mature content that may include coarse language, sexual references, and/or graphic violent images which may be disturbing to some. Mature pages are recommended for those who are 18 years of age and older.
If you are 18 years or older or are comfortable with graphic material, you are free to view this page. Otherwise, you should close this page and view another page.
It's sheer perfection. My precious G-virus. No one will ever take you away from me...
~ William Birkin, before being ambushed by HUNK and the Umbrella Security Service.
~ G in his fifth form.

William Birkin (also known as G after mutation) is an extremely knowledgeable and intellectual virologist for the Umbrella Corporation that discovered the G-virus and the person responsible for the Raccoon City Outbreak. He is one of the two secondary antagonists of Resident Evil 0 (the other being Albert Wesker), and the main antagonist of Resident Evil 2


Early life

William Birkin started working for Umbrella as a researcher when he was only 16 and was assigned to a management training facility under Dr. James Marcus. While there he became good friends with a fellow researcher, Albert Wesker and the two became Marcus’s best students. Birkin and Wesker began research on the t-Virus, which they continued after the shut down of the training facility and their transfer to the Arklay Mountain facility. He had a friendly rivalry with Alex Wesker during the latter's time working for Umbrella.

Birkin was proud to be the youngest researcher to ever work for Umbrella until Alexia Ashford arrived on the scene. Though only 10 years old, Alexia became head of the Antarctic Research facility and ignited great jealously from Birkin since his coworkers praised her constantly. He focused on his research and, after no results for a long time, finally created the Hunter, B.O.W. Birkin focused completely on his research from that point onward, even when Alexia was announced to be “dead” in 1983.

Birkin and Wesker killing James Marcus

William Birkin assisting Albert Wesker to assassinate James Marcus

In 1988, he and Wesker helped to assassinate their former mentor, James Marcus and were put in charge of t-Virus research with Birkin himself being credited for the t-Virus’s creation. By that point, he had married his assistant, Annette, and had a daughter, Sherry.

Discovering the G-virus

Later, Birkin and Wesker began experimenting with the NE-a parasite. One of their test subjects, Lisa Trevor, was the only subject who fully accepted the parasite into her system, while the others died shortly after it had been implanted. Birkin noticed this and examined her body structure to find that she'd had a Progenitor virus variation injected into her body many years before.

This had absorbed the mutagenic organisms in her body, resulting in a new virus that Birkin called the G-virus. After receiving approval to begin further research into the G-virus, Birkin and his wife were transferred to an Underground Research Facility in Raccoon City that had been established specifically for the project. Birkin also bribed the head of the Raccoon City Police, Chief Irons, to ensure the project remained under wraps.

Arklay Mountains Incident

After Birkin and Wesker began looking into the Outbreak of the t-Virus in the Arklay Mountains area, they were shocked to find out that it had been caused by their former mentor, James Marcus, returned from the grave. Knowing that the truth could not get out for the sake of his career, Birkin activated the self-destruct on the training facility, destroying all of the evidence of his involvement in the conspiracy to get rid of Marcus.

Becoming his own creation

Birkin finally completed his G-virus in 1998 and planned to use his research to become an Umbrella’s Executive. However, due to conflicts with his superiors, Birkin decided to sell his research to the government. He requested that the military retrieve him, but a unit of Umbrella’s Security Service, the Alpha Team, got to him first. Birkin was left to die with gunshot wounds from an overexcited soldier and his virus research was stolen.
William Birkin dying

A dying William Birkin about to use the G-Virus

Before dying, he injected himself with the G-virus, becoming a terrible monster, dubbed "G". After mutating, G went after the USS team that stole his research, cutting all of them down except the leader, HUNK, and two other members. Vials containing the T-Virus were smashed in the fight, releasing them onto rats, which caused the outbreak throughout Raccoon City. G returned to his lab where he rendered the staff unconscious and infected some of them. However one of the staff members, Monica, stole a G-virus sample and planned to escape to the surface with it. Unfortunately for her, G tracked her down and implanted her with one of his G-virus Spawn embryos. Since Monica’s DNA was not compatible with Birkin’s, she was killed when the embryo tore out of her body. Later, he began wandering around the Raccoon City Police Department and came across a few of the survivors of the outbreak, including his daughter, Sherry. G implanted one of his embryos into Brian Irons, who was not compatible and killed when the embryo burst from his body and also killing a reporter named Ben Bertolucci who locked himself in the precinct's cell. He was able to plant an embryo in Sherry and even called out to her a few times. As he attacked Claire Redfield, Leon S, Kennedy, Ada Wong, and Sherry again and again, G continued to mutate until he faced off against Leon and Claire in his final form, finally meeting his end when the train they were on blew up.


  • Accelerated Healing: Because of the G-virus in his body, Birkin has fierce regenerative abilities which make him biologically immortal and very difficult to defeat. However, being in a huge explosion destroys him completely.
  • Accelerated Mutation: He also has the ability to mutate or 'evolve' whenever his genetic makeup has taken extensive damage, becoming more powerful and deformed with each mutation. This can also be considered a weakness, as his fifth and final form was too deformed to combat properly.
  • Reproduction: He has also demonstrated the ability to implant G-virus Spawn embryos in other people. If the person’s DNA is compatible with Birkin’s DNA, they will be combined with it, but if not, the embryo will tear out of their bodies when it has developed enough. They will then evolve into more mutated monstrosities.

Form 1

William Birkin (2)

G AKA, William Birkin in his first form.

In this form, Birkin looks the most like his human self but has had a large increase in muscle mass. One of the most noticeable mutations of this form is the enlarged right arm with a huge, tumor-like eyeball near the shoulder. Since this form lacks any natural weapons, Birkin wields a piece of pipe that he tore from a guardrail with his superhuman strength. He can also throw it or swing it multiple times in succession.

Strangely, when Annette remembers how he killed the USS soldiers, Birkin is seen possessing talons that he slices them apart with. However, these claws may have simply atrophied away from lack of use, due to the unpredictability of the G-virus.

Form 2

William Birkin (3)

G AKA, William Birkin in his second form.

In this form, Birkin’s head has been forced down into the chest to be replaced by a new skull, the right hand has sprouted large, bone talons, and two new arms have begun to develop underneath the originals. In this form, G possesses all the same abilities as the previous one but now has the added advantage of its sharp talons. In this form, it attacks by slashing and stabbing at its opponents with its new claws.

Interestingly, this form of G managed to recognize Annette, to some extent at least. When it found her, it hesitated and looked at her for a few moments, but attacked her when she drew a gun on it, recognizing her as a threat.

Form 3

William Birkin (4)

G AKA, William Birkin in his third form.

In this form, G has lost all of its outer skin to reveal a more muscular body. Countless spike-like projections emerge from the chest while William Birkin’s face has almost utterly faded into the torso. The left arm has also gained talons, though these ones are more like nails rather than the ones made of bone on the right. G has also grown to far beyond the size of a normal human and its primary arms have grown beyond that of a normal human, moving back to become more secondary appendages. The second set of arms from the previous form have become fully functional and developed claws. The new head has fully developed and another tumor-like eye has developed on G’s left leg. In this form, G has most of the same combat characteristics of its previous form, except that it is far more acrobatic, able to use powerful jumping slashes and even a bizarre roundhouse kick where it follows up with a slash from two of its arms.

Form 4

William Birkin (25)

G AKA, William Birkin in his fouth form.

In this mutation, G has become a quadrupedal mutant, utilizing its four primary limbs to move around. The skull and jaw have extended to accommodate the newly formed mouth, which is little more than a gaping maw surrounded by spikes, combining with the spikes that used to cover its torso. Despite having a rather bulky body, G is quite agile and quick in this form and can run, climb walls, and jump all around with little effort. The eyes on its shoulders may or may not be its actual eyes, which would indicate that the ones in its skull are simply for show. G can attack by impaling enemies with the spikes around its mouth, spitting acidic slime out of its mouth, swiping at enemies with its forearms, and biting at them.

Form 5

William Birkin (26)

G AKA William Birkin in his Final Form

Without a doubt, G's fifth form is the most twisted out of all of the mutations, after experiencing massive physical damage, the creature has mutated into a formless abomination of flesh, spikes, limbs, and tentacles. It is able to move only by attaching its largest tentacles to a stationary object and squirming forward with its lesser ones. It is unknown if G would have continued to mutate into other forms after this one. However, this is unlikely since it has already become a formless blob and has nothing left to mutate into. But this mutation is not produced from evolution like the other forms, instead, it is produced by the virus responding to the heavy damage the creature had taken.

Though while extremely weakened in this form, G isn't defenseless. It attacks by swinging its massive tentacles at its prey and hurling wreckage. It also has two highly bizarre attacks, spitting up recently consumed zombies to attack its enemies and ejecting its own mouth to strike at them.

It also has some level of intelligence, since it realized the train car it was on was about to explode and screamed “SHERRY!” However, this creature was unable to escape and destroyed by the explosion. Even the G-virus wasn't strong enough to counter the damage, finally putting an end to G.

Resident Evil Films

William Birkin (Film)

William Birkin in Resident Evil film.

William Birkin makes a brief cameo in the first Resident Evil movie. Like in the video game of the same name, William Birkin is one of the scientists that work for the Umbrella Corp. However, unlike the video game, Birkin never injected himself with the G-virus and slowly begin to mutate into the monster known as G. And it was never confirmed if he and Albert Wesker killed James Marcus to take over his research. What happens to William Birkin in this version is currently unknown.


Resident Evil 2

  • "It's sheer precious G-virus. No one will ever take you away from me."
  • "Oh, you finally come."
  • "Sorry, but I won't just hand over my life's work..."

Resident Evil 0

  • "It just doesn't make sense. Do you honestly believe this to be the real identity to that crazy young man? Impossible! And yet somehow it is true that Umbrella will be finished."
  • "What are you going to do?"
  • "You can't be serious! I refuse to abandon my work, I've just finished my research on the T-Virus but I need a little more time to complete the more powerful G-virus!"
  • "Fine. In the meantime, something must be done by that madman. As I recall, you are equipped with an assault to destruct device in the basement. I'll find it, set it off and annihilate the place to nothing more than a pile of rubble."





  • William Birkin was voiced by Diego Matamoros in Resident Evil 2, and T. J. Rotolo in Resident Evil: The Umbrella Chronicles, Resident Evil: The Darkside Chronicles, and Resident Evil: Operation Raccoon City.
    • William Birkin was also played by Jason Isaacs in the first Resident Evil Movie, who also provided the villainous role of Lucius Malfoy in the Harry Potter series, Captain Hook in the 2003 Peter Pan film, Ra's al Ghul in Batman: Under the Red Hood, and Satan in Castlevania: Lord of Shadows.
  • William Birkin was originally going to be the main antagonist in the movie; Resident Evil: Apocalypse, but Jason Isaacs left the product of undisclosed reasons. So a character named Sam Isaacs was created for the film to both fill the space and honor Jason Isaacs.


           Resident Evil Villains

Umbrella Corporation
Albert Wesker | Alex Wesker | Alexander Slater | Alexia Ashford | Alfred Ashford | Frederic Downing | HUNK | Jack Krauser | James Marcus | Morpheus D. Duvall | Nicholai Ginovaef | Oswell E. Spencer | Red Queen | Sergei Vladimir | Spence Parks | Timothy Cain | Undertaker Units | UT Commander | VECTOR | William Birkin

Los Illuminados
Bitores Mendez | Ganado | Osmund Saddler | Ramon Salazar

Curtis Miller | Excella Gionne | Ricardo Irving

Carla Radames | Glenn Arias

Other Establishments
Edonian Liberation Army | Hive-Host Capture Force | The 3rd Organization | The Family | Veltro | WilPharma Corporation

Baker Family
Eveline | Jack Baker | Lucas Baker | Marguerite Baker

A-Virus | B.O.W. | Ganado | Las Plagas | Lisa Trevor | Majini | Nemesis | Nosferatu | Tyrant 00 | Zombie Dog | Zombies